The concept of dendrimer technology and particularly dendrimers are well known in the art. In general, a dendrimer is a large molecule having a sphere-like shape and includes a core with outer branches for holding functional groups.
Dendrimers are unique, highly branched, organic molecules that represent a breakthrough in polymer synthesis. Dendrimers are considered to be novel because of their size, shape, and physical or chemical properties. Dendrimers represent an example of synthetic organic molecules having uniform size and 3-dimensional structures. A promising feature of dendrimers is that they can be synthesized to have various internal structure and various surface properties. Because of the multiple reaction sites on the dendrimer molecules they can be combined with a number of different compounds.
Dendrimers are considered nanotechnology since the size of a dendrimer molecule is typically in the nanometer range. In general, the dendrimers are comprised of three components a) a core material; b) a highly-uniform branched polymers attached in step-wise layers to the core and c) a nano-scaled 3-dimensional surface structure, commonly spherical. While the synthesis of dendrimers is known, it is oftentimes difficult and time consuming, thus the cost of dendrimers can be relatively expensive costing thousands of dollars per pound. The technology and use of dendrimers remains limited at least partly due to the high costs of the dendrimers. However, various dendrimer patents and publications on dendrimers include laundry lists of proposed applications or uses for dendrimers.
An example of a proposed use of a dendrimer in “wound treatment” is shown in Balogh U.S. Pat. No. 6,224,898. Balogh et al discloses that an antimicrobial agent comprising a metal-containing compound is distributed on or in a dendrimer polymer for applying to a specific type of wound, namely, “burn wounds”. Balogh et al states his “dendrimer silver nanocomposite” is applied to a wound by a spray or is applied to a cloth substrate and then applied to a wound. While Balogh et al. conducts tests he concludes that his antimicrobial agent is effective “in vitro” for treatment of wounds.
While the dendrimers generally do not have any antibacterial properties the Cooper et al. U.S. Pat. No. 6,440,405 discloses formation of a quaternary ammonium functionalized dendrimer that does derive its antibacterial properties from the dendrimer itself. In Publication No. US 2002/022012 Cooper et al. goes on to propose “surface treatments” using a dendrimer biocide-silver nanocomposite as an antimicrobial agent. Cooper et al. prepares his biocide-silver nanocomposite by reacting the dendrimer biocide disclosed in his U.S. Pat. No. 6,440,405 with a silver compound. Cooper et al. then incorporates his biocide-silver nanocomposite into various surface coatings to provide the coating or surface with antimicrobial activity. Cooper et al. points out the use of the dendrimer with biocide-silver nanocomposite as being effective against agents such as anthrax. Cooper et al. specifically points out the incorporation of his dendrimer silver nanocomposite into “protective coatings or paints, personal products such as cosmetics, industrial products, hospital products, and sanitation of swimming pools and spas.” Cooper et al. goes on to point out that his dendrimer silver nanocomposite can be “immobilized onto the surface to create efficient antimicrobial surfaces for use as biomaterial, anti-fouling paints, and other similar devices.” Thus, Cooper et al. teaches the use of the biocide-silver nanocomposite within the structure or some type of coating to make antimicrobial surfaces.
The Tomalia et al. U.S. Pat. No. 5,714,166 discloses the use of dendrimers for “pharmaceutical and agricultural applications” More specifically, Tomalia et al discloses dense star polymers can be associated with a bioactive agent, a diagnostic agent or a therapeutic/diagnostic agent. Tomalia et al. teaches the use of the dense star polymers in pharmaceutical and agricultural applications. He specifically points out the transporting of genetic material through a cellular member and into a cellular nucleus with a dendrimer polymer.
The Tomalia et al U.S. Pat. No. 4,507,466 discloses the uses of dendrimers for emulsifier for oil or water emulsions, as wet strength agents in the manufacture of paper and agents for modifying the viscosity in aqueous formations such as paints.
The Tomalia et al. U.S. Pat. No. 4,694,064 discloses the use of dendrimer in the production of molecular composites and as crystalline modifiers for polymeric materials.
In the above references it is evident that the dendrimers or dendrimer biocides have been combined with various biocidal agents to produce antibacterial products that can be incorporated into articles or coatings to rid surfaces of bacteria. In contrast, the present invention has found that one can incorporate dendrimers with an antimicrobial agent directly into a fluid to control microbial activity in the fluid in order to render the fluid safe for either consumption or recreational uses. In addition, the invention includes a fluid treatment method that permits one to rid or at least inhibit microbial growth in the fluid and when the dendrimer antimicrobial agent is spent permits one to remove and recycle the dendrimer for combining with fresh antimicrobial agents.